AFRRI investigators will evaluate (1) combinations of IL-10 with gentamicin and a fluoroquinolone for its potential survival improvement by 30% or more after combined injury at LD70/30;(2) its timing optimization of the IL-10 therapeutic treatment, and (3) combination of IL-10 and G-CSF for its potential survival improvement by more than that produced by each alone after combined injury at LD70/30. The contractor will test IL-10 (an anti-inflammatory mediator) + gentamicin + a fluoroquinolone and IL-10 + G-CSF + gentamicin +a Fluoroquinolone as combined candidate therapeutic countermeasures for radiation combined injury. The proposed candidate drugs have demonstrated therapeutic efficacy in survival from radiation injury. Because bacterial infections are evident beginning 2 d after combined injury, topical application of gentamicin and oral administration of a fluoroquinolone have been shown to improve survival from combined injury . This study will also test this combined candidate countermeasure regimen.